Barium is often released into wastewater in industrial manufacturing operations. The barium concentration of industrial wastewater is generally toxic and should be removed from the wastewater for proper disposal. If barium is not removed from wastewater before disposal, barium can seep into the groundwater and soil. Groundwater in the midwestern region of the United States contains soluble barium. Exposure to barium may cause gastrointestinal disturbances, muscular weakness, and increased blood pressure, among other things.
During water treatment, membrane scaling due to barium is well known. In order to protect membrane from scaling, a pretreatment for barium is required prior to pumping the water to membrane unit. Several methods have been developed to reduce barium concentration from groundwater and wastewater.
One method to reduce barium concentration is chemical precipitation of barium carbonate through lime softening. However, barium precipitation and removal by lime softening is a highly pH dependent process. The water must have a pH between 10.0 and 10.5 for efficient barium precipitation. Another method to reduce barium concentration is chemical precipitation of barium sulfate using coagulants such as alum or ferric sulfate. However, barium removal by a conventional coagulation process requires a two-stage precipitation system due to the slow precipitation kinetics of barium sulfate.
Another method to reduce barium concentration in water is the use of ion exchange systems. However, ion exchange systems require frequent resin regeneration using additional chemicals. The treatment, handling and disposal of the regenerant chemicals are a major drawback to this technique. Reverse osmosis (RO) systems have also been employed to reduce barium concentration in water. However, in RO systems, scaling often occurs on the RO membrane if the barium reacts with other contaminants in the water to form barium sulfate or barium carbonate. This reduces the efficiency of the RO unit and may damage the membrane. A final method employed to remove barium from water involves adsorption of barium onto magnesium hydroxide. However, this process is also a highly pH dependent process. The water must have a pH of approximately 11 for efficient barium adsorption and removal.
All of the above processes comprise several operational steps, are complicated, or are costly. Therefore, there is a need for a simple and cost effective method to remove barium from water